Process for utilization of ammonia



Apr, 17, 1923. 1,452,009

` J. F. WAIT 1` PROCESS FOR UTILIZATION OF AMMONIA' Filed may 25, 1920 2sheets-sheet 1 j? 1 /Yl'A/SE i Pfff/05171 ralf zf Bral/gsm- Apr. .17,1923; 1,452,009

' J. F. WAIYI mocsss Fon UTILIZATIDN or' AMMONIA 4 Fmr/Mn ramener/Winnz/ww l Zwin/m1 :myn/w www fitr.

Patented Apr. 17, 1923. l l UNITED srarizsf PATENT OFFICE.

JUSTIN F. WAIT, v0F NEW YORK, N. Y.

PROCESS FOR UTILIZAT'ION OF AMMONIA.

Application Med May 25, 1920. Serial Nb. 384,097.

To all whom. it may confiera.: other element or elements. A mmenia as Beit known that'Jtrs'rix F Warr, citisuch may be reeoijered from .thisammonia zen of the United States, residing at New compound by heatingwithsuitable reagent? York city, in the county of New York and Anexample of this 1s the recovery fofjpnifi 00 State of New York, hasinvented certain. monia chloride' in the' acid hydrolysis of new anduseful Improvements in Processes 'some organic nitrite. c f forUtilization of Ammonia,- of`whch the The iixed.amn'ionia., asthe'chloridepln following is a specification. the example cited, may bereleased as'freeor In chemical processes it is frequently unattachedammonia by heating with l'nllk' 65 necessary torccover ammonia gas inorder (of lime. This is in accordance with to effect chemical economy.One way of hcard practice, i y 1 complishinf. r this. is in the wel]known iuane The heatlng converts the fixedjam'mona ner of absorbing theammonia ,iras in water in to free ammonia and distills off the newfl andsubsequentlyregenerating the ammonia =formed freeammonia together withsuoi 70, by heating the aqueous ammonia .thus other free ammoniaas mayhave been pres-` formed either with diri-rt or indirect steam. entin themixture.V The heat. drives otl the ammonia gas with As inthe ease beforementioned, consideri some water vapors` ,which are` condensed, ableenergy isexpended in driving ofth'e forming aqueous ammonia. n Normall)Y`this ammonia. lithfa slight increase 4infthe 75 regeneration of thcammonia is carried out amount o f energy the cycle rnzrwbel 4soco'`under approxiinatcl)v atmospheric pressure. trollcd as to convert theenergy thus expend;

'l`he amount of heatnercssary for the rw cd into a useful form yieldingarefrigeratihg generation of the ammonia A:gas in thiA frianeffect. l nerdescribed is considerable. lt requires In a .like 'manner it frequentlyV4lutpp`ens80 but a small percentage increase in heat to that a chemicalprocess consumes a quantity i i `regenerate this ammonia gas underpressure of ammonia., part of whlch is released aga! such that coolin rhy means` of water ohtainin the form of a dilute aqueous solittiioiiu`-able from usual sources will liqucfy the anilittle value, as such. Thisdilute'aqfleriusal'lil monia. monia may beconcentrated and passedzbai'k.85 This liquefication may also he arrominto the system-thus formingaQlosedcyel plislwd lrv mechanical means of obtaining and effecting higha'monia econom. the pressure such as passingr therapto-stron; lf thisconcentration is controlled and 'a tho rehenes-alors through acompressor. ln small 4amount ofudditional energy eXpdnded, such a raseit might he advisable to cool.the a conversion of the energy froma-wasteful 90 gases hc-foro compression as well as after lo a usefulform may'be accomplished. lIn compression. this case it is advisable tocontrol the process After the ammonia isthus liquclicdit is so as tov:yield nearly `anhydrous ammonia passed into a system of lowerprcssurf` in for the refrigerating effect and to rea'bsorb which theliquefied animonia is allowcd to this in` some of the dilute aqueousammonia 95v evaporate. thus creatingr a refrigcratin;r cl'- in order toproduce the strength desired. fort similar in eflect to an ordinaryrefrig- In systems operating in thisvmyanner it'is erat'iingr machine.desirable tohave a.l1ow moist-ure content in Thifrases al'tvrevaporation are used dithe ammonia after it is driven out'f'ofsolurcctlv in the ,gaseous form. or ri-absorbed tion by the heat. Forthis purpose the 100 viclf ing a puri` aqueous solution which will usualdephlegrnators, rlumns. etc4 would againl. la used in thichemicalprocess, In la used but in`` addition to this drying this manner aprocess.v requiring thecxpendicolumn is placedin the system prior to theturc of enor; f as heat. may he controlled so cooling or 'condensingunits. This A'drying as to convert this energy, which would othercolumnconsists of atower or its equivalent 105 wiso he wasted. into a usefulform. [n order filled with lime or other suitable dehydratto accomplishthis control there is required a. ingp agent. I relatively small amountof additional Y*In the. accompanying drawing-s Figs. 1, energy. n 2, and3 are diagrams illustrating the process ln soun processes. ammonia isrecovered and modilications thereof. v. i 110 :is fixed ammonia. ln suchan 4instance the Fig. 1 shows a chemical process absorbammonia iscombined chemically with some ing ammonia vapors at one period or step ithe abso l EVB and regenerating anlnonia vapors at another geribd orstep. It is assumed that this abprbing and regenerating is carried outin 4a group of knownI chemical reaction units high pressure by means ofa pump This ution passes into a regenerator shown at l in the fgure.-Here it is 4I ieated, as by means of steam, and aminoniavapors aredriven ofi', the pressure still being in excess of the pressure at tower5, and of such deree that the vapors on passing into a con- 5ensei'v2will be condensed by suchcooling water as is available under normaloperating conditions,

The liquefied ammonia is passed through a throttle valve 7 `and into arefrigerator 3 in which it is allowed to evaporate due to rption of heatfrom the medium which it is desired should refrigerated. The ammonia1now, in vapor form, is assed into the chemical reacting vessels 4 w ereit enters into reaction, thus completing the cycle. It will beunderstood that the reaction in these vessels is such as to finallydeliver ammonia vapor as referred to in the start.

Fig. 2 shows a chemical process in which fixed ammonia is produced, theammonia being recovered again :is free ammonia by passing through thedescribed 'cycle producing a useful refrigeriig'iing effect. The fixedammonia is delivered in solution from the chemical reaction vessels4 tothe pump 6 by?? which it is pumped into the regenerator 1 maintainedunder pressure Asuch that the ammonia arising therefrom may be liquefiedby ordinary condenser 2 maintained at approximately the saine pressureas the discharge liiie from re eneratorl,

he fixed ammonia is freed by heating with some reagent such as milk oflime which is pumped from supply 9 into regenerator 1 by means of a pump8 After condensin in 2 the liquefied ammonia is passed throng a throttlevalve 7 into the lower pressure system where it produces refrigerationin refrigerator 3 by being allowed to rate. e evaporated ammonia' isabsorbed in a scrubbin twer 5 and the solutioniof ammonia o tothe'chemical vessels to be again reacted on, producing more fixedammonia, thus completing the cycle.

In such a system as this, additional new ammonia will have to be addedat some point, possibly directly to vessels 4 in order to make up forthe quantities used up in the major reaction or lostv mechanicall or asother tay-products. In this case the ted cooling water in thc.

the desired 'strength is returnedA formed.

In Fig. 3 is'shown a process for effecting a use of heat otherwisewasted in the concentration of weak liquors of aqueous ammonia.- Theprinciple of o eration is similar to that of the previous y describedsystems. y

lVeak ammonia. liquor f chemical or other reaction vessels 4 isf into afeed tank 10. Part of the weak liquor is fed therefrom through a pump 6into a regenerator 1. pum Y 1^ is used and gravity flow resorted to orthe concentrated liquor. Vapors issuing from regenerator 1 undersuitable pressure are vcooled and liquefied in. oon'- densor 2 andpassed 'into refrigerator 3, which is maintained under.4 low pressurewhere the liquid evaporates causing refri eration. T he ump 1'? may beused to a vantage in ordIr to permit of llowrpressure operation i`nregenerator 1. Great heat ieconomy is obtained by making pump 1^- asteam driven uqit exhausting into the generator coils. The vapors fromrefr er- The pump 6 may be omitted if a i ator 3 pass into anabsorptionunit 5` into Y which weak liquor is fed from the tank 1 0 and brought uptol any desired strength, discharging into the reaction units?! in whichis performed the chemical or other reaction using the strong aqueousammoniar A slight `back pressure on units 3 and 5, will permit of theproduction of aqua ammania of very high strength.

In this manner the heat energy of distillation ofV the ammonia isconverted into useful energy a's -a refrigerant instead f being wastedas isjdofne in present lantfo tion.,

The regenei'ator 1. in ad ition to having the usual de hlegmators andcolumns may be assisted in ehy rating the ammonia va ors by passagethrough a drying unit 1,2 which ma contain a. dehvdrcting unit such 'asllme.

he free antimonia4 is released from the chemical reaction vessels atrelativel low pressureyandmy invention involves t e application to thisammonia. of hi her pressures and the liquefaction thereof iy the aid ofeoolin water.- The ammonia ma then be expan ed and vaporized in the prouction' of arefrigerating effect. A relatively small quantity of energythus expended in the creation of higher pressure results in theutilization `of s. lar e amount of ener 'otherwise wasted. oncentrationand purification of ammonia occurring in or contamiyby the developmentof siitable to;

liqiefaction by ordinary meins.

- he foregoing; is descriptiveof soin of the iso possible applicationsof my process of converting wasted into useful energy but I do not limitany claims to the example cited.

l claim: f

l. The process of utilizing ammonia re-l sulting from a chemicalreaction in which free ammonia is released at lowpressnrc, comprisingabsorbing the ammonia released in water or suitable Solvent, heating thesolution formed and thus drivin r off ammonia vapors, cooling the vaporsat'high pressure thus formed under pressure liqiiefy the ammonia,passing tlie liquid ammonia into a system of lower pressure and allowingit to evaporate, thus causing a refrigerating effect, and subsequentlyusing the ammonia in the chemical reaction.

2. A process comprising u chemical reaction in which ammonia is used andgiven oli' at low temperature, raising the pressure of and coolingeaidiammonia to liquefy same, Missing the liquid ammonia into a syst insaid chemical reactio tem o lower pressure, allowing the ammonia toevaporate therein thus causing a refrigerating effect, recovering theammonia, and using the same in the chenlical reaction again.

3. A process eomprisin action in which ammonia in solution is used -andfixed ammonia is rodiiced at low pressure, which consists 1n adding asuitable reagent to said fixed ammonia to free the ainiiionia, addingsiiflicient heat to the mixture to drive off the aiiinionia ata highpressure, cooling and liquefying the ammonia, evap oratin r .said liquidammonia at a lower pressure, a isorbing in asuitable liquid the vaporfrom said evaporating li uid and again utif-lizin the ammonia in soution thus formed a chemical re- 4f. A process L I comprising a chemicalreaetion in which ammonia is uged and is given suiiiciently to oli' atlow pressure, raising the pi'eaelu'e of and cooling said ammonia toliquefysame passing the-liquid ammonia into a system of lower pressure,allowing the ammonia to evaporate therein thus causing a refrigeratingeffect, recovering the ammonia, and using the same in the chemicalreaction again.

'5. A process comprising a chemical reac tion in which ammonia is usedand fixed ammonia is produced, transferring the saine to a regeneratorand heating the sume therein with tlie'uddition of a reagent toAgenerate ammonia, liquefying the saine at high pressure in a condenser,expanding the same in a refrigerator,'and subsequently reusing the sumein thc chemical reaction.

6. A process comprising using ammonia in a cheinicalreuction producingan :im-nioniacal by-product, regenerating said byproduct, liquefying theammonia by cooling under increased pressure, expanding the same in :isystem of' lower pressure, thus )rfiducing a refrigcriiting effect, andsu ise- 'quently using the ammonia in the reaction again.

7. A process comprising a chemical reaction in which ammonia is used andgiven oil' in one stage, regenerating th: ammonia in another stage,increasing the pressure of the regenerated ammonia, liquef ing the lameby cooling, passing the liquid into a tystem of lower pressure,evaporating the Yammonia thus causing and subsequently reusing theammonia in the chemical reaction.

In bestiiii'on whereof, I aiiix my signature in presence o twb'witnesses.

JUSTIN F. WAIT.

Witnesses:

Howaiui G. WILSON, JOHN C. WAIT.

a rei'rigerating eli'ect,`

